Arizona silver belt., 1887-09-24

I
The brilliant meteors ana shooting
stars which are seer with such fre,
qoeney ia Arizona, owing 10 The clear-
ness ot the atmosphere, are never
ceasing source of wonder and delight
to the beholder Very few people
have an intelligent idea OF ths phe-
nomena of shooting.stars, although
the present generation are sufficiently
enlightened not to be inspired with
Tear by the appearance Of showers of
these meteors, which IN earlier ages
caused CONSERVATION among inhabi-
tauts Of Eastern countries, who be-
heved that the end Of the world had
come. Astronomers now tell MS that
the celestial spaces are crowded with
innumerablc minute bodies moving
around the sun in every possible or
bit, The word crowded is used IA a
relative sense, as these invisible bod
les, called meEeoroids, may not average
more than QUE in a million cubic miles,
and yet their total number exceeds all
calculation The earth is constantly
encountering them in ITS motion
around the sun, and they are burned
BY passing through the upper regions
OF our atmosphere.
How these bodies could be 50 sud.
denly burned and emit SO intense a
light as to be visible hundreds Of miles
away was problem that remained
for long time unsolyed, and until
the discovery Of the mechanical theory
of heat. tits now known that heat is
only a certain form of motion that hot
air differs from cold air onlyin a more
rapid vibration Of its molecules, and
that it communicates its heat 70 other
bodies by setting their molecules ia
vibration. II has been ascertained
that the temperature rises one degree
when body moves through the air at
the rate Of 1875 feet per second With
higher velocities the increase Of tenn.
perature was found to be proportional
to the square Of the velocity, beiug q
degrees with velocity Of ESQ feet, 16
degrees with one Of 500 feet per sec-
ond, etc,
The earth moves in its orbit at the
rate Of $1,000 feet per second, and IL ii
met a meteoroid at rest, our atmos-
pbere would strike 1t with this yeloe-
ity, 50 that the rise Of temperature
would be nearly 100000 degrees,
When, as is commonly the case, the
meteoroid is moving toward the earth,
the velocity, and therefore the potion
tial temperature, will be still higher.
Meteoroids have been known to move
in direction opposite to thas Of the
earth with a velocity of rs miles per
second, SO that the relative velocity
with which they met our atmosphere
was "a miles per second This CORE.
spends TO temperature Of between
three and four million degreesi
Sometimes these meteoroids are SO
large and dense as to pass through
our atmosphere and reach the earth
without being entirely consumed and
we then have an aerolite, Asthe pas
sage only occupies a few sscoads the
heat has not always time % penetrate
far into the interior, and golatizes
emily the outer portions. Then when
the body strikes the denser portion oF
the atmosphere, the resistance becomes
so enormous that the aerolits is egten
broken to pieces with such violence
that il seems to explode, and loud
detonation often follows.
II has been computed that meteors
become visible At a height f75 miles
and disappear at height Of about SIS
miles.
| Professor Newton discovered that
the swarm Of rneteoroids which cause
the November showers reyolys around
the sun in definite orbit, which In
tersects the orbit Of The earth al j
| point which the latter now passes on
November 18th. The best authorities
believe that the time Of revolution of
these meteoroides in their orbits ia asa
years. So meteoFic showers arc pre-
dlcted every S3 years, with great GER
tarnty, Smaller showers are visible
yearly about August 9th Or 10th.